Wallabies prop Tom Robertson faces a race against time to be fit for next year's Rugby World Cup after scans confirmed he would need surgery on his knee to repair a ruptured anterior cruciate ligament (ACL).

The 24-cap loosehead prop suffered the injury during training last week as the Wallabies prepared for their final Rugby Championship clash with Argentina in Salta.

Coach Michael Cheika said at the time the injury appeared "significant" and after undergoing scans back home in Australia the extent of the damage was confirmed.

A report on Rugby Australia's website said Robertson would have surgery next week with the estimated recovery time between six and nine months.

The shorter end of that timeframe could see Robertson return for the final few months of Super Rugby, which runs from February until early July next year due to the World Cup, which starts on Sept. 20.

Cheika's immediate concern, however, is to form his squad for the Wallabies' end-of-year tour.

James Slipper, who was banned for two positive cocaine tests this year, could see himself back in contention for a spot due to Robertson's injury.

Slipper, who normally plays loosehead prop, has been playing tighthead in Australia's National Rugby Championship but Cheika said he would probably only consider him as a loosehead.

Sekope Kepu and Allan Alaalatoa have also recently begun to play both sides of the scrum and are likely to vie with Scott Sio for the number one jersey on the tour.

Sio was replaced at halftime in the match against the Pumas on Saturday as the Wallabies went in 31-7 down at the break.

With Kepu and Alaalatoa prominent in getting their side over the gain line, Australia produced the largest comeback in Rugby Championship history to win the game 45-34.

The Wallabies play the All Blacks in the third Bledisloe Cup test in Yokohama on Oct. 27 before they play Wales, Italy and England.